Motuora Restoration Society (http://motuora.org.nz) is recognised by the New Zealand Department of Conservation as the lead community agency for the restoration of Motuora, an 80 ha island in the Hauraki Gulf, New Zealand. Since 2003 the Society has taken responsibility for the Island’s day-to-day management as well as developing and implementing the Island’s long term restoration strategy. Our aspiration is summed up in our statement “It is our dream that future generations will enjoy a forest alive with native birds, reptiles and insects”.

Figure 1 – Aerial view of the Island before planting began. Area to bottom left has been sprayed in preparation for planting (Photo from cover of 2007 Motuora Native Species Restoration Plan).

Figure 2 – Aerial view of the Island after completion of the pioneer planting. (Photo by Toby Shanley)

Background. Motuora is located on the east coast of New Zealand’s North Island near Auckland City. Motuora would once have been tree-covered and have hosted a wide range of native plants, invertebrates, reptiles and birds, particularly burrow-nesting seabirds. It was visited by early Polynesian settlers, later Māori, who would have initially camped, but later lived more permanently on the Island raising crops and harvesting fish, shellfish and presumably seabird eggs, chicks and adults. European settlers later occupied the Island, burning off most of the bush to encourage growth of grasses for their grazing livestock.

Towards the end of the farming period in the 1980s most of the Island’s native flora and fauna were gone. Interestingly however, there were never breeding populations of introduced mammalian pests on the Island so the remnant ecosystem had not been impacted by mice, rats, mustelids, hedgehogs, possums, goats, pigs or deer.

From about 1987 onwards both Government and members of the public began to take an interest in the Island and to promote the idea of adopting it as a predator-free bird habitat. Discussions continued over the next few years and by 1992 a sub-committee of the mid-North Royal Forest and Bird Protection Society had been formed and, in partnership with the Department of Conservation, drew up the first ‘strategy plan’ for the Island. Work parties began seed collecting, trial tree planting, weeding and fencing upgrades. By 1995 it had become apparent that the project could best proceed by way of an independent group dedicated to the task and the Motuora Restoration Society was formed.

The work on Motuora was designed to be a true restoration project combining firm ideas about the model ecosystem desired and a ‘bottom-up’ approach (vegetation-invertebrates-reptiles-birds) timing planting and introductions in a logical sequence. The historical presence of species on Motuora was inferred from comparisons with other less modified islands off the north east of the North Island, and particularly those from within the Rodney and Inner Gulf Ecological Districts, and using paleological information collected from the adjacent mainland. Motuora Restoration Society has resisted the temptation to add iconic attractive species not originally present on the Island which might have raised the profile of the project.

Works carried out. The Society and its volunteers have contributed many thousands of hours to the restoration of the Island since 1995, raising and planting more than 300,000 native seedlings. This was particularly challenging with the logistics of working on an island without a regular ferry service or wharf. The project also included seabird and other species translocations, monitoring, weeding and track maintenance as well as fundraising.

The framework adopted began with reforestation so that appropriate habitat could be reinstated. A nursery was set up and seeds were collected from the Island, from nearby islands and, when necessary, from the mainland. With the exception of some areas of higher ground providing panoramic views from the Island, the land area was prepared (by weed-killing rampant kikuyu grass) and planted with hardy, wind and salt tolerant tree species. Once the trees were established, the canopy closed and sufficient shelter available, less hardy species and those requiring lower light levels were planted among the pioneers. Today the planting of 400,000 trees of pioneer species is all but complete; and the raising and planting of ‘canopy’ and less hardy species continues.

In terms of fauna, invertebrate populations were surveyed and have been monitored as the forest has matured. One species, Wētāpunga (Deinacrida heteracantha) has been introduced. Four reptiles have been introduced: Shore Skink (Oligosoma smithi), Duvaucel’s Gecko (Hoplodactylus duvaucelii), Raukawa Gecko (Woodworthia maculata) and Pacific Gecko (Dactylocnemis pacificus). One small land bird – Whitehead (Mohoua albicilla) has been translocated with 40 individuals moved to the Island. Four seabird species have been attracted or translocated to the Island including the Common Diving Petrel (Pelecanoides urinatrix), and Pycroft’s Petrel (Pterodroma pycrofti).

Results. The project has restored Motuora from a pastoral farm (dominated by introduced grasses, weeds and only a small remnant fringe of naturally regenerating native forest) to a functioning native ecosystem, predominantly covered in early succession native forest with an intact canopy.

Initially the population of invertebrates was dominated by grassland species but the range and population size of forest dwellers has now much improved and the invertebrate fauna is now rich and plentiful (although rarer and endangered species are still to be added). An initial suite of populations of flightless invertebrates remain depauperate. Whitehead, an insectivorous bird species, has flourished with a current population of several hundred. At this early stage in the introduction of native fauna it is possible to report successful breeding and, for the most part, sufficient survival of initial colonisers of the species introduced to suggest that new populations will be established. Sound attraction systems have led to initial breeding of Fluttering Shearwater (Puffinus gavia) and Australasian Gannet (Morus serrator).

Partnerships. Management of the Island is shared with the Department of Conservation (DOC) who administer the site on behalf of the Crown. DOC has legal commitments to engage with and act on behalf of the general public and particularly with iwi (Māori) who have generally expressed strong support for the restoration project and are expected to have co-management rights over the Island in the future.

Over the years the combined efforts of DOC staff, University researchers, the committee, thousands of volunteers and a host of donors and sponsors have worked hard to bring the Island to its present state.

Future directions. A sustained effort will continue to be required each year on biosecurity and weeding programmes. It will be many more decades before the forest matures and seabird and reptile populations reach capacity levels and a substantial workload is anticipated in managing and monitoring the emerging ecosystem for many years to come.

Acknowledgements: The success of the project is reinforced by the fact that the Society has maintained a close collaboration with a range of scientists and have inspired the active support and engagement of so many volunteers. We thank all our inspiring volunteers and the following participating academics and researchers who have contributed to the project over the past ten years: Plants: Shelley Heiss Dunlop, Helen Lindsay (contractor). Reptiles: Marleen Baling (Massey University), Dylan van Winkel (consultant), Su Sinclair (Auckland Council), Manuela Barry (Massey University). Invertebrates: Chris Green (DOC), Robin Gardner-Gee (Auckland University), Jacqueline Beggs (Auckland University), Stephen Wallace (Auckland University). Birds: Robin Gardner-Gee (Auckland University), Jacqueline Beggs (Auckland University), Kevin Parker (Massey University), Richard Griffiths (DOC), Graeme Taylor (DOC), Helen Gummer (DOC contractor). The restoration project has been supported financially though grant aid received from a wide range of funders.

Figure 1. The Peron Peninsula divides the two major bays of the Shark Bay World Heritage Area, Western Australia.

Introduction. In 1801, 23 species of native mammals were present in what is now Francois Peron National Park. By 1990 fewer than half that number remained (Fig 1.). Predation by introduced foxes and cats, habitat destruction by stock and rabbits had driven many native animals to local extinction.

Project Eden was a bold conservation project launched by the WA government’s Department of Conservation and Land Management (CALM -now Dept of Parks and Wildlife) that aimed to reverse extinction and ecological destruction in the Shark Bay World Heritage Area.

The site and program. Works commenced in Peron Peninsula – an approx. 80 km long and 20 km wide peninsula on the semi-arid mid-west coast of Western Australia (25° 50′S 113°33′E) (Fig 1). In the early 1990s, removal of pest animals commenced with the removal of sheep, cattle and goats and continued with the control of feral predators. A fence was erected across the 3km ‘bottleneck’ at the bottom of the peninsula where it joins the rest of Australia (Fig 2) to create an area where pest predators were reduced to very low numbers.

Figure 2. The feral proof fence was erected at the narrow point where Peron Peninsula joins the mainland.

Methods. Cat baiting involved Eradicat® cat baits, which were applied annually during March–April at a density of 10 to 50 baits/km2. Cat baiting continued for over 10 years, supplemented with a trapping program, carried out year round over a 8 -year period. Cat trapping involved rolling 10 day sessions of leghold trapping along all track systems within the area, using Victor Softcatch No. 3 traps and a variety of lures (predominantly olfactory and auditory).Tens of thousands of trap nights resulted in the trapping of up to 3456 animals. Fox baiting involved dispersal of dried meat baits containing 1080 poison by hand or dropped from aircraft across the whole peninsula. Baiting of the peninsula continues to occur annually, and removes any new foxes that may migrate into the protected area and is likely to regularly impact young inexperienced cats in the population, with occasional significant reductions in the mature cat population when environmental conditions are favourable.

Malleefowl were raised at the Peron Captive Breeding Centre from eggs collected from active mounds in the midwest of Western Australia. Woylies were reintroduced from animals caught in the wild from sites in the southwest of Western Australia, with Bilbies sourced from the Peron Captive Breeding Centre, established by CALM in 1996 to provide sufficient animals for the reintroductions. The centre has since bred more than 300 animals from five species

Monitoring for native mammals involved radio-tracking of Bilbies, Woylies, Banded Hare Wallabies, Rufous Hare-Wallabies, Southern Brown Bandicoots, Chuditch and Malleefowl at release, cage trapping with medium Sheffield cage traps and medium Eliots, as well as pitfall trapping of small mammals. The survey method for cats utilized a passive track count survey technique along an 80 km transect through the long axis of the peninsula. The gut contents of all trapped cats were examined.

Figure 3. Once foxes were controlled and cats reduced to about 1 cat per 100 km of monitored track, sequential reintroductions of five locally extinct native animals were undertaken. Woylies were first introduced in 1997 from animals caught in the wild at sites in southwest Western Australia.

Figure 4. Tail tag being fitted to a Bilby. (Bilbies were re-introduced to the Peron Peninsula in 2000, from animals bred in the Peron Captive Breeding Centre.)

Results. Monitoring has shown that two of the reintroduced species – the Malleefowl and Bilby – have now been successfully established. These species are still quite rare but they have been breeding on the peninsula for several years The Woylie population may still be present in very low numbers, but despite initial success and recruitment for six or seven years, has gradually declined due to prolonged drought and low level predation on a small population. Although the released Rufous Hare-wallabies and the Banded Hare-wallabies survived for 10 months and were surviving and breeding well, they disappeared because of a high susceptibility to cat predation and other natural predators like wedge-tailed eagles. Although some predation of Southern Brown Bandicoot has occurred and the reintroduction is still in the early stages, this species has been breeding and persisting and it is hoped that they will establish themselves in the thicker scrub of the peninsula.

Lessons learned. We found that the susceptibility to predation by cats and foxes varies considerably between species. Malleefowl are very susceptible to fox predation because the foxes will find their mound nests, dig up their eggs up and eat them – consequently wiping them out over a period of time. As cats can’t dig, Malleefowl can actually exist with a fairly high level of cats. Bilbies live in their burrows and are very alert so they can persist despite a certain level of cats. But the Rufous Hare-wallaby and the Banded Hare-wallaby are very susceptible to cat predation and fox predation due to their size and habits.

Examination of the period of time when species disappeared from the Australian mainland showed that there was a sequence of extirpations, reflecting the degree to which the species were vulnerable to pest predators. The ones that survived longest are those that are less vulnerable. This suggests that if complete control of predators is not possible (considering cat control is extremely difficult), it is preferable to focus on those animals that are least vulnerable. While it could be argued that reintroductions should be delayed until such time as all the cats and foxes have been removed, such a delay (which might take us 10, 20 or even 100 years) is likely to exceed the period of time many of these species will survive without some sort of assistance. It is likely to be preferable to proceed with reintroductions although we might be losing some animals.

Future directions. As with the majority of mainland reintroduction projects, level of predator control is the key to successful establishment of reintroduced fauna. The Project is currently under a maintenance strategy and future releases, which included the Western Barred Bandicoot (Perameles bougainville), Shark Bay Mouse (Pseudomys fieldi), geoffroi), Greater Stick-nest Rat (Leporillus conditor) and Red-tailed Phascogale (Phascogale calura) are on hold until improved cat control techniques are available. Despite the uncertain future for reintroductions of these smaller species, ongoing feral animal control activities and previous reintroductions have resulted in improved conditions and recovery for remnant small native vertebrates (including thick billed grass wrens, woma pythons and native mice), and new populations of several of the area’s threatened species which are once again flourishing in their original habitats.

Acknowledgements: the program was carried out by Western Australia’s Department of Parks and Wildlife and we thank the many Departmental employees, including District and Regional officers for their assistance over the years, and the many, many other people that have volunteered their time and been a part of the Project over the years, for which we are very grateful.

Introduction. Neds Corner Station is Victoria’s largest private conservation property. This 30,000 hectare ex-sheep and cattle station was purchased for nature conservation by Trust for Nature (Victoria) in 2002.

The property occupies the driest area of the state with an average annual rainfall of only 250 mm. As such, it has strong ecological links to the arid regions of Australia and Australia’s rangelands. Neds Corner sits strategically at the hub of an extensive network of public and private conservation lands bordering or close to the Murray River in Victoria, New South Wales and South Australia. The reserve is bordered on three sides by the Murray Sunset National Park and borders frontages along the Murray River and associated anabranches for more than thirty kilometres, where the River Red Gum (Eucalyptus camaldulensis) dominated riparian zone connects with Chenopod Shrublands, Semi-arid Chenopod Woodlands and Chenopod Mallee Woodlands. Trust for Nature’s restoration efforts are targeted at restoring woodland connectivity across the property to improve habitat extent and condition for woodland and mallee plants and animals, including the nationally threatened Regent Parrot (Polytelis anthopeplus). A biodiversity survey in 2011 found 884 native species at Neds Corner Station, including 6 threatened birds and animals, 77 threatened plants, and 21 species new to science. Trust for Nature continues to find new records for the property.

Fig. 1. Highly degraded area (near watering points) in 2003 just after Trust purchased the property.

Fig. 2. Same photopoint in 2014 showing extensive natural regeneration of Low Chenopod Shrubland after removal of livestock and extensive treatment of rabbits.

Planning for recovery. In 2002, when Trust for Nature first took on the property, the land was severely degraded from continuous over grazing by stock, rabbits and native herbivores; weed infestations; historic clearing of extensive areas of woodland for firewood and forage; and lack of flooding. Native vegetation was sparse over much of the property, soil erosion was extensive and the floodplain and semi-arid woodlands were all showing signs of extreme stress.

In the early years of ownership, management focussed on addressing the most obvious of these threats, with a focus on rabbit control and weed control. In 2010, with funding support from The Nature Conservancy, Trust for Nature prepared a Conservation Action Plan for the reserve, using the Open Standards for Conservation process, and a subsequent management plan. These planning documents identified the key biodiversity values on the reserve, the major threats to these values and the strategies to reduce threats and improve condition to achieve agreed ecological goals.

Works undertaken. Trust for Nature’s first action was to remove the livestock to allow the regeneration and growth of native vegetation. Stock fencing was decommissioned to enable free movement of native fauna, and new exclosure fencing to protect sites of cultural and ecological significance were also constructed. Major efforts were made to reduce rabbit numbers through the use of warren ripping, fumigation and 1080 baiting across the property. To date, over 20,000 warrens have been treated. Direct seeding and tubestock planting in the Semi-arid Woodland areas of the property have been continuous, with the cessation of a cropping licence, over 500 ha direct seeded in one year as part of an Australian Government funded project. In partnership with the Mallee Catchment Management Authority, environmental water allocations have been used to inundate areas of Neds Corner, providing a vital lifeline to many of the plants and animals that inhabit the riverine billabongs and floodplain forests. Artificial water points and superfluous tracks have been closed. Targeted fox and other feral animal programs are continuous.

Fig 5. Highly degraded ‘Pine paddock’ in 2003 just after the Trust purchased the property.

Fig 6. Pine paddock from same photopoint in n2014 after exclosure fencing, rabbit control and extensive direct seeding of trees and shrubs in 2007 (and again in 2010). The grasses all naturally regenerated.

Results. In the 14 years since domestic stock removal and the ongoing control of rabbits and weeds, there has been a dramatic increase in the cover of native vegetation, notably from natural regeneration (Figs 1-4) but also from extensive supplementary planting and direct seeding (Figs 5-8). In 2011, wide spread natural germination of Murray Pines occurred across the woodland sections of the property and Sandhill Wattle (Acacia ligulata) seedlings were observed on one rise where no parent plant was known to occur, indicating a viable seed bank may exist. The vulnerable Darling Lilies (Crinum flaccidum) continue to extend their range, given favourable weather conditions and the continuous control of herbaceous threats to the extent required to ensure adequate recruitment of these key flora species. Bird surveys undertaken for one of the targeted projects within Neds Corner over the past 10 years show an encouraging increase in reporting rates of Brown Treecreeper (Climacteris picumnus victoriae) (>x2 increase), Chestnut-crowned Babbler (Pomatostomus ruficeps) (>x2% increase) and Red-capped Robin (Petroica goodenovii) (>x20 increase).

Fig.7. Revegetation plantings in 2008

Fig 8. Same revegetation planing line in 2013.

Current and future directions. Trust for Nature are due to revise their CAP and have identified the need to undertake recovery actions at a greater scale. They are currently investigating the feasibility of re-introducing some fauna species back into Neds Corner Station that haven’t been found in the region for decades, provided there is sufficient habitat to sustain them.

Acknowledgements. As a not-for-profit organisation, Trust for Nature (Victoria) relies on the generous support of many individuals, organisations and government entities. The main project partners to date include The Nature Conservancy, RE Ross Trust, Yulgilbar Foundation, Australian Government, Mallee Catchment Management Authority, Parks Victoria, Department of Environment, Land, Water & Planning, Mildura Rural City Council, Northern Mallee Region Landcare, Traditional Owners and the thousands of hours volunteers contribute to Neds Corner Station.

Posted on5 March 2016byteinm|Comments Off on Conserving and restoring biodiversity of the Great Barrier Reef through the Representative Areas Program (RAP)

Key words: Coral reef, no take zones,

The Great Barrier Reef is the world’s largest coral reef ecosystem (344,400 square km) and a World Heritage Area on the north-east coast of Australia. It contains a high diversity of endemic plants, animals and habitats. It is a multiple-use area with different zones in which a wide range of activities and uses are allowed, including tourism, fishing, recreation, traditional use, research, defence, shipping and ports. Components of the ecosystem have been progressively showing symptoms of decline.

Coral Trout is one of more than 1625 fish found on the Great Barrier Reef

Existing ecosystems. Coral reefs are like the building blocks of the Great Barrier Reef, and comprise about seven per cent of the ecosystem. The balance is an extraordinary variety of other marine habitats and communities ranging from shallow inshore areas to deep oceanic areas over 250 kilometres offshore and deeper than 1000 metres, along with their associated ecological processes. The abundant biodiversity in the Great Barrier Reef includes:

Some 3000 coral reefs built from more than 400 species of hard coral

Over one-third of all the world’s soft coral and sea pen species (150 species)

Six of the world’s seven species of marine turtle

The largest aggregation of nesting green turtles in the world

A globally significant population of dugongs

An estimated 35,000 square kilometres of seagrass meadows

A breeding area for humpback whales and other whale species

More than 130 species of sharks and rays

More than 2500 species of sponges

3000 species of molluscs

630 species of echinoderms

More than 1625 species of fish

Spectacular seascapes and landscapes such as Hinchinbrook Island and the Whitsundays

215 species of bird

Diver injecting Crown of Thorns Starfish

Impacts on the ecosystem. The main threats to the Great Barrier Reef ecosystem are:

Restoration goals and planning. A primary aim of the Great Barrier Reef Marine Park Authority (GBRMPA) is to increase biodiversity protection, with the added intent of enabling the recovery of areas where impacts had occurred. A strong foundation for this has been achieved through the Representative Areas Program, by developing a representative and comprehensive network of highly protected no-take areas, ensuring they included representative examples of all different habitat types.

The rezoning also provided an opportunity to revise all the zone types to more effectively protect the range of biodiversity.

A further aim was to maximise the benefits and minimise the negative impacts of rezoning on the existing Marine Park users.

These aims were achieved through a comprehensive program of scientific input, community involvement and innovation.

An example of Green Zones (marine national park) and Yellow Zones (conservation park)

Monitoring. An independent scientific steering committee with expertise in Great Barrier Reef ecosystems and biophysical processes was convened to define operational principles to guide the development of a comprehensive, adequate and representative network of no-take areas in the Marine Park (Fernandes et al 2005). Science (both biophysical and social science) provided the best available information as a fundamental underpinning for the Representatives Areas Program.

There are currently over 90 monitoring programs operating in the Great Barrier Reef World Heritage Area and adjacent catchment. These programs have largely been designed to address and report on specific issues, location or management.

implementing a Reef Recovery program to restore sites of high environmental value in regional areas — regional action recognises the variability of the Reef over such a large area and the variability of the issues and interests of communities and industries in each area.

More and bigger fish: Larger fish are important to population recovery as they contribute more larvae than smaller fish. James Cook University research shows the network of no-take marine reserves benefits species of coral reef fish targeted by fishers (especially Coral Trout), with not only more fish, but bigger fish in reserves — some zones have around twice as much fish biomass compared to zones open to fishing.

Improved fish recruitment: Research in the Keppel Islands suggests increased reproduction by the more abundant, bigger fish in reserves. This not only benefits populations within those reserves, it also produces a ‘spill over’ when larvae are carried by currents to other reefs, including areas open to fishing.

Improved resilience: The spillover effects also mean the connectivity between reserve reefs is intact. Spatial analysis shows most reserve reefs are within the dispersal range of other reserve reefs, so they are able to function as a network.

Sharks, dugongs and turtles: These species are harder to protect because they are slow growing and slow breeding. They are also highly mobile, moving in and out of protected zones. Despite this, available evidence shows zoning is benefiting these species.

Reduced crown-of-thorns starfish outbreaks: Outbreaks of crown-of-thorns starfish appear to be less frequent on reserve reefs than fished reefs. This is particularly important as Crown-of-thorns Starfish have been the greatest cause of coral mortality on the Reef in recent decades.

Zoning benefits for seabed habitats: Zoning has improved protection of seabed habitats, with at least 20 per cent of all non-reefal habitat types protected from trawling.

How the project has influenced other projects. In November 2004, the Queensland Government mirrored the new zoning in most of the adjoining waters under its control. As a result, there is complementary zoning in the Queensland and Australian Government managed waters within the Great Barrier Reef World Heritage Area.

The approach taken in the Representative Area Program is recognised as one of the most comprehensive and innovative global advances in the systematic protection and recovery of marine biodiversity and marine conservation in recent decades and has gained widespread national international, and local acknowledgement of the process and outcome as best practice, influencing many other marine conservation efforts.

Stakeholders. As a statutory authority within the Australian Government, the Great Barrier Reef Marine Park Authority is responsible for managing the Marine Park. However, as a World Heritage Area, management of the ecosystem is complex jurisdictionally.

Both the Australian and Queensland governments are involved in managing the waters and islands within the outer boundaries through a range of agencies. GBRMPA works collaboratively with the Queensland Parks and Wildlife Service through the joint Field Management Program to undertake day-to-day management of the Great Barrier Reef, including its 1050 islands, many of which are national parks. The program’s activities include surveying reefs and islands, dealing with environmental risks such as ghost nets and invasive pests, responding to incidents, maintaining visitor facilities, and upholding compliance with Marine Park legislation and the Zoning Plan.

A wide range of stakeholders have an interest in the Great Barrier Reef, including the community, Traditional Owners, a range of industries and government agencies, and researchers. The public, including the one million people who live in the adjacent catchment (around 20 per cent of Queensland’s population), benefit from economic activities. In recent years, the number of tourists carried by commercial operators to the Great Barrier Reef averaged around 1.6 to 2 million visitor days each year (GBRMPA data) with an estimate of an additional 4.9 million private visitors per annum.

Resourcing. The resourcing required for rezoning of the Great Barrier Reef over the five-year period of the RAP (1999–2003) was significant. It became a major activity for the agency for several years, requiring the re-allocation of resources particularly during the most intense periods of public participation. However, the costs of achieving greater protection for the Reef are readily justified when compared to the economic benefits that a healthy Great Barrier Reef generates every year (about AUD$5.6 billion per annum).

Introduction. Introduced rabbits, rats and mice have caused widespread and severe ecological impacts on the native flora, fauna, geomorphology and natural landscape values of Subantarctic Macquarie Island. Major impacts include the destruction of almost half of the island’s tall tussock grassland and the depletion of keystone palatable species, a decline in the abundance and or breeding success of a range of seabird species due to habitat degradation, increased exposure to the elements and predation, as well as increased slope erosion. The Macquarie Island Pest Eradication Project is the largest eradication program for rabbits, ship rats and mice in the world.

The overall goal of the pest eradication project was to eradicate rabbits, rats and mice from Macquarie Island to enable restoration of the island’s natural ecological processes including the recovery of plant and animal communities impacted by these feral species.

Works undertaken. The Tasmania Parks and Wildlife Service developed a plan for the eradication of rabbits and rodents on Macquarie Island that was approved by the federal Minister of Environment in 2006. Following lengthy negotiations and a donation of $100,000 by the World Wildlife Fund (WWF) and Peregrine Adventures, funding of $24.6 million for the project was secured in June 2007 through a joint state and federal government agreement.

Toxic baiting of rabbits, rats and mice using aerial baiting from helicopters across the island conducted over two winters to minimise the risk of mortality for non-target seabirds. Mitigation measures were taken to reduce seabird mortality in six species after the 2010 baiting, including the introduction of calicivirus (Rabbit Haemorrhagic Disease Virus) before further baiting in May 2011 – (See Evaluation Report 2014)

On-ground follow-up with hunters and dogs, which was originally expected to take about three years but took seven months (2012) following the outstanding success of the calicivirus in substantially reducing rabbit numbers.

Five months after the last known rabbit was killed, the monitoring phase of the project commenced in April 2012 to search for any evidence of live rabbit or rodent presence on the island and continued for two years, with some 92,000 km travelled over 3 years (2011-2014).

Following two years of monitoring without any evidence of the target species, the project to eradicate rabbits and rodents from Macquarie Island was declared successful in April 2014. A variety of established research/monitoring projects on threatened native plant species, invasive plant species, plant communities and ten species of seabirds on Macquarie Island have been used to provide biologic data on changes in abundance, distribution and condition (see Evaluation Report 2014).

Vegetation. Vegetation recovery was well underway by 2013, when vegetation biomass on the island had increased by a factor of five to ten compared with 2011 levels.

The initial stage of vegetation recovery following rabbit eradication was a rapid increase in the biomass of the pre-existing communities. The pre-eradication vegetation was a highly modified disturbance disclimax with the majority of the lower slopes of the island dominated by Short Subantarctic Bent Grass (Agrostis magellanica), where regular soil disturbance by introduced species encouraged the establishment of herbaceous primary colonisers including willowherbs (Epilobium spp.), Subantarctic Bittercress (Cardamine corymbosa), Waterblinks (Montia fontana) and the introduced Annual Meadow Grass (Poa annua). Subantarctic Buzzy (Acaena magellanica) covered large areas. Tall Tussockgrass (Poa foliosa) was reduced to small pockets or individual plants on steep slopes, whilst the Macquarie Cabbage (Stilbocarpa polaris) was confined to very steep coastal slopes and Prickly Shieldfern (Polystichum vestitum) survived in exclosures.

More recent monitoring shows bare ground declining, with further increases in vegetation cover and successional changes. Taller/longer lived species have greatly reduced the cover of primary colonisers (mostly short lived, small herbs). The three introduced plant species on the island, all of which are primary colonisers, have fluctuated in abundance post-eradication.

Annual meadow grass has decreased markedly in abundance away from areas of seal and seabird disturbance, while Mouse-ear Chick Weed (Cerastium fontanum) and Garden Chickweed (Stellaria media) initially increased in abundance between 2011 and 2013 but have since declined.

The previously ubiquitous Subantarctic Buzzy has declined dramatically with competition from other species, while the previously less common Little Burr (Acaena minor) is now more prevalent.

The megaherbs Macquarie Cabbage and Macquarie Megadaisy (Pleurophyllum hookeri) and Tall Tussockgrass are beginning to spread and establish across the island (Figure 1). It is predicted that a combination of these species will become dominant in much of the coastal and slope vegetation over time, with Tall Tussockgrass already increasing in cover in many areas. The prickly shieldfern is expanding from a few remnant populations by recruitment or regeneration in former exclosures, as well as establishing in new locations.

Seabirds. A combined total of 2418 individual native birds were recorded as killed via primary and secondary ingestion of broadifacoum poison during the winter baiting of 2010 and 2011. These numbers are minima, since many were predated before detected and others died at sea. Kelp Gull (Larus dominicanus) sustained the largest mortality (n=989), followed by Giant Petrels (Macronectes spp; n=761), Subantarctic Skua (Catharacta skua) (n=512) and Black Duck (Anas superciliosa) (n=156). Existing monitoring programs enable the population consequences of this mortality to be evaluated for both species of giant petrel and for skua, however baseline data for gulls and ducks on Macquarie Island are lacking. The mortality event was associated with a 25-30% reduction in the breeding populations of both giant petrel species, however ongoing monitoring reassuringly shows both populations to have stabilised and appear to have resumed the increasing trajectory that they were undergoing before the mortality event. Skua were heavily impacted, with breeding numbers reduced by approximately 50% in monitored sites. There is minimal sign of recovery for this species in recent years. The response of this species to the sudden removal of a primary prey item (rabbits) and the consequent flow-on ecosystem impacts is the focus of current investigation.

With the success of Macquarie Island Pest Eradication Program, we are seeing rapid recovery in the breeding habitats of both burrow and surface nesting species. Grey Petrel (Procellaria cinerea), which re-established on Macquarie Island after the successful eradication of cats in 2000, have continued to increase and Blue Petrel (Halobaena cerulea) which were previously restricted to rat-free offshore rock-stacks, have returned to mainland Macquarie Island and continue to expand in both distribution and number. Dedicated survey effort in coming seasons will provide quantitative estimates of the response of the burrow nesting seabird assemblage to Macquarie Island Pest Eradication Program.

Lessons. Perhaps one of the most important lessons learned is the value of biological monitoring data, before during and after such an eradication program, which provides the basis for effective adaptive management as well as evaluation of success or otherwise.

The other salutatory lesson is the complex biological inter-relationships that exist and a need to more explicitly factor in the consequences of the ‘unknowns’ in associated risk assessments.

Acknowledgement. Thanks to Micah Visoiu for most recent vegetation data.

Threats and Impacts: Carp (Cyprinus carpio) are believed to impact on native fish communities by increasing turbidity, up-rooting delicate shallow-rooted vegetation, competing with native fishes and other aquatic fauna for food and space, and indirectly promoting the development of toxic algal blooms.

All of the currently available methods for Carp control have limitations. Integrated Pest Management (IPM) involves the application of a range of technologies applied simultaneously, and focussing on achieving broader objectives (e.g. improved habitat) rather than simply reducing pest numbers.

Broad aim and specific objectives: The objectives of this project were to apply a range of Carp control techniques, as an integrated package, to:

intensively reduce Carp at a particular location, and measure the response;

achieve a significant reduction in damage caused by Carp using existing techniques; and,

demonstrate to the community the commitment to on-ground control.

The study was conducted at four lagoon sites, two in the Condamine River catchment, and two in the Macintyre river catchment.

Methods: One lagoon in each catchment was selected as an experimental site for intensive carp removal, and the other was used as a reference site which received no carp treatment.

Each site was sampled on eight occasions for the following response variables: water quality (temperature, pH, conductivity, turbidity, dissolved oxygen, light penetration, available forms of nitrogen and phosphorus); phytoplankton biovolume and diversity; zooplankton biomass and diversity; benthic macroinvertebrate abundance and diversity; native fish abundance, biomass and diversity; carp abundance, biomass and size distribution; and abundance of piscivorous birds and turtles.

One sampling event was conducted before the carp reduction treatment and a further seven samples were performed after Carp reduction. Carp removal employed a variety of methods based on boat electrofishing, gill nets, fyke nets, angling, commercial-scale netting and traps, and screens to prevent re-entry of Carp.

Findings: In Rainbow Lagoon (one of the experimental sites), Carp removal achieved an estimated 51% reduction in abundance and 43% biomass reduction, compared with 41% abundance and 33% biomass reductions in Warra Lagoon (the other experimental site). Reduction of Carp biomass by approximately 30 kg per ha allowed a threefold increase of more than 90 kg per ha in native fish that are eaten by larger fish species and fish-eating birds.

The size and weight of Carp removed differed markedly between Warra Lagoon and Rainbow Lagoon. Rainbow Lagoon had large numbers of small Carp, while Warra Lagoon had relatively large numbers of big Carp, with relatively few small individuals. The differences in Carp populations between lagoons are likely to result in different ecosystem responses over time.

Boat electrofishing was the most effective method of Carp removal used; fyke nets were the second most effective method, while the number of Carp removed by angling was far lower than other methods.

A succession of ‘transient’ responses to Carp reduction was observed in treatment lagoons. Whilst the exact nature of succession differed between lagoons, the generalised pattern following Carp reduction was evidenced as (i) an increase in biomass of large zooplankton; (ii) an increase in abundance of benthic macroinvertebrates; and (iii) increased biomass of gudgeons (Hypseleotris spp.) and Bony Herring (Nematalosa erebi).

These results suggest that of the full set of potential ecosystem responses to Carp reduction, only a subset may be demonstrated in individual locations because of the influence of local drivers and constraints. Due to a range of factors, the environmental responses of several variables, including water quality, macrophytes, zooplankton and macroinvertebrates, could not be linked to Carp control.

Lessons learned and future directions:Modest reductions in Carp biomass can provide significant benefits for native fish and, if continued, may be expected to translate into longer-term increases in native fish populations.

Posted on30 January 2014byemrprojects|Comments Off on The potential for Mozambique Tilapia to invade the Murray–Darling Basin and the likely impacts: a review of existing information

Key words: Tilapia, pest fish, invasion risk, Native Fish Strategy

Threats and Impacts: Mozambique Tilapia (Oreochromis mossambicus) is a major pest fish species in Australia (Fig 1). A successful invader, it has managed to dominate natural waterways into which it has been introduced. It is not currently found in the Murray–Darling Basin; however, it has established thriving populations in catchments neighbouring the Basin. In some places, it is only a short distance from the northern headwaters. There is a high risk that this species will be introduced to the Basin.

Project aims and methods: Despite the high risk of introduction, prior to this project minimal work had been done to estimate the potential range Tilapia might occupy in the Basin, or to predict its possible impacts on natural, economic or social assets. This project set out to review available literature and assess likely impacts in an attempt to provide some information about these potential threats.

In order to estimate the potential range of Tilapia in the Murray–Darling Basin, this project set out to to:

predict the range in the Basin where Tilapia may survive through colder winter temperatures;

determine the length of the feasible breeding season (including the number of broods possible in that time) in different ranges; and,

determine the portion of the year in which Tilapia may feed and is therefore likely to have impacts on ecological processes through the food web.

This included:

estimating the lower temperature tolerance for Tilapia based on literature and survival rates of populations already infesting locations in Queensland;

identifying the minimum winter temperatures recorded at different locations throughout the Basin; and,

using the distribution of native fish with similar temperature tolerances to Tilapia as a surrogate.

Findings: Tilapia has a wide and varied diet and can occupy a diverse range of habitats, however, the one factor that appears to affect Tilapia is its vulnerability to cold temperatures. Based upon minimum temperature tolerated by Tilapia and the minimum water temperature data available, Tilapia have the potential to infest the northern Basin in Queensland and parts of New South Wales, through the western inland catchments of NSW and down to the Lower Lakes and lower Murray in South Australia. This equates to a distribution occupying approximately half of the MDB.

Tilapia is capable of sustaining reproducing populations under the conditions found in much of the MDB, as breeding and feeding can occur for significant portions of the year. In the northern parts of the Basin, and many southern parts, median water temperatures could see a breeding season of at least 3–6 months in duration with around 4–6 broods for each female in each breeding season.

Tilapia impacts have been recorded in a number of locations both in Australia and overseas. The key impacts recorded include major declines in commercial and traditional fisheries, fish extinctions, destruction of beds of aquatic plants) and declines in water quality. Some of the predicted direct impacts of Tilapia on the Murray–Darling Basin include:

direct predation by Tilapia;

competition for resources (food, habitat);

destruction of macrophytes and other aquatic plants used as breeding or nursery habitat by native species;

undermining river banks due to destruction of river plants and nesting behaviour.

Review of recent studies indicate that Tilapia consume juvenile native fish, including members of genera that occur in the Murray–Darling Basin, such as Rainbowfishes (Melanotaeniidae), Carp Gudgeons (Hypseleotris spp.), Hardyheads (Atherinidae), Bony Herring (Nematalosa erebi) and Glassfish (Ambassidae). It is possible that the potential preying of tilapia on native fish has been underestimated.

Lessons learned and future directions: This project highlighted that invasion of the MDB by Tilapia could be disastrous for many (up to 18) native fish species of the MDB. Areas and species most at risk from Tilapia and the likely impacts if invasion occurred were identified. The study recommends a ‘prevention is better than cure’ approach with respect to Tilapia invasion and highlights education and awareness as a key factor. This review should be most pertinent in areas close to current distribution of wild tilapia populations (i.e. north-eastern MDB).

Stakeholders and Funding bodies: This project was funded through the Murray-Darling Basin Authority’s Native Fish Strategy.

Threats and Impacts: Introduced to Australia in 1925 as a potential mosquito control agent, the fish Gambusia (Gambusia holbrooki) (Figs 1 and 2)is now present in almost every major Australian drainage, including the Murray-Darling Basin. Gambusia are extremely aggressive, harassing, predating and attacking native fish; and are thought to also pose a significant threat to many amphibians and invertebrates.

Broad aim, specific objectives and methods: This project explored in aquaria how aggressiveness of Gambusia changed according to the relative abundance of two native fish species (western carp gudgeon Hypseleotris spp. and juvenile Golden Perch Macquaria ambigua). Five treatments were run involving combination of Gambusia to native fish ratios and temperatures. The project was designed to improve understanding of how Gambusia might behave when it colonises new areas and how behavioural responses might be affected by efforts to control their numbers.

Findings: The study found that Gambusia were highly aggressive towards both species of native fish and that aggressiveness increased when Gambusia were outnumbered by native fish. The study also found that the type of aggressive behaviour by Gambusia (e.g. biting or chasing) was specific to the native species it was interacting with. Gambusia were shown to dominate the available habitat within the tank very shortly after introduction. The high aggression and dominance behaviour exhibited by Gambusia when outnumbered assist this species when invading new habitats and may also have implications for eradication efforts aimed at this invasive species.

Lessons learned and future directions: The increased aggression by Gambusia when outnumbered potentially means that control efforts that reduce the abundance of Gambusia but don’t fully eradicate them may not be beneficial to native fish in some cases. The research suggested that aggressive interactions from Gambusia may not decrease as a result of eradication efforts.

Stakeholders and Funding bodies: This project was funded through the Murray-Darling Basin Authority’s Native Fish Strategy.

Threats and Impacts: Redfin Perch (Perca fluviatilis) is an alien fish species that has been established in Australia for more than 150 years. Although a popular recreational angling target in some regions, it has a range of deleterious impacts on native fish, through predation and competition for resources, and as a vector for a virus (epizootic haematopoietic necrosis virus). Despite the threat posed by this species, there are major deficiencies in current knowledge and policies in regards to controlling existing populations and responding to new infestations. In New Zealand and Australia the control of Redfin Perch has been found to be most effective in small lakes and ponds using physical removal techniques such as nets and traps, as well as mid-water trawling and electrofishing at night.

Project objectives and methods: The objectives of this project were to:

undertake a detailed literature review of species biology to identify weaknesses that could be exploited in control programmes;

conduct field trials of potential control techniques;

complete an investigation of behaviour and movement using acoustic technologies; and,

provide recommendations for a future control programme, including scoping of sterile feral technology.

This study included a detailed literature review of Redfin Perch biology to identify any potential weaknesses that could be exploited in control programs. Field trials were then performed in an impoundment (Suma Park Reservoir) on the central tablelands of New South Wales, known to contain an abundant population of Redfin Perch, and a riverine site in the Gwydir catchment. The trials were designed to investigate the effectiveness of physical removal of Redfin Perch using a combination of electrofishing, panel (gill) netting (with and without herding), fyke nets and clover-leaf traps with several attractants (laser lights, glow sticks, magnets and berley). The study also used underwater acoustic cameras (DIDSON) to examine Redfin Perch behaviour in response to each of the attractants. Separate trials were undertaken in winter and summer. Additional field trials were undertaken in a riverine site in the Gwydir catchment during summer.

Given the limited understanding of the species movement patterns and the importance of this information to targeting control techniques, an acoustic tagging study was undertaken in Suma Park Reservoir.

Figure 1 A cloverleaf trap such as those used during field trials (Photo courtesy of Dean Gilligan)

Figure 2 The focus species for this study, Redfin Perch (Photo courtesy of Dean Gilligan)

Findings: The review of Redfin Perch biology highlighted several key aspects that could be exploited in future control programmes:

timing of reproduction – target removal prior to or during spawning events;

In the removal trials, catch rates in fyke nets and cloverleaf traps were relatively low across all three trials (winter and summer in reservoir and summer in river) with standard panel nets and electrofishing being the most effective methods. The clover-leaf traps were not effective at catching Redfin Perch, either with or without attractants within the traps. Catch rates in cloverleaf traps and fyke nets were too low to draw any conclusions relating to improvements in catch efficiency resulting from the use of the attractants trialled. However, assessment of the response of Redfin to the various attractants using DIDSON imagery revealed that glow sticks and lasers do have the potential to be used as attractants, particularly at night.

The acoustic telemetry study indicated that most fish occupied the downstream end of the dam, with only up to two individuals spending extensive periods of time within the upstream reaches of the impoundment. Overall, fish spent 90% of the time within the top 10 m of the water column, possibly due to lower dissolved oxygen concentrations below this depth.

Lessons learned and future directions: Overall this project has resulted in the compilation of valuable information on Redfin Perch that can contribute to its future management. In particular:

passive fishing techniques/traps that rely on luring/attracting fish into a certain area (e.g. clover-leaf traps) are not very effective;

they appear to be much more susceptible to being caught in nets that target/intercept fish while moving (fyke and panel nets);

electrofishing is effective in the short-term and on a small scale, but may not be cost effective/practical in the long term as abundance of the target population declines;

glow sticks and laser lights were found to be effective attractants at night, but optimal deployment methods need to be established that minimise trap-avoidance of those fish attracted;

juveniles form large schools, whereas adults were more solitary; and,

movement data indicates the top 10 m of the water column and areas around the deeper downstream reaches of impoundments are occupied most frequently and may be appropriate areas to target removal efforts.

Stakeholders and Funding bodies: This project was funded through the Murray-Darling Basin Authority’s Native Fish Strategy.

Posted on26 January 2014byemrprojects|Comments Off on Design and installation of a novel wetland Carp harvesting set up at Lake Bonney, South Australia

Key words: Carp, pest fish control, Lake Bonney, Native Fish Strategy

During 2009–2010, Lake Bonney (near the township of Barmera in SA) received 26 gigalitres of environmental water from the Murray River. It was anticipated that Carp (Cyprinus carpio) would accumulate in large numbers at the lake inlet as water was delivered (Fig1), providing a unique opportunity to trial a wetland Carp separation cage (WCSC) for controlling the estimated 50–100 tonnes of this species in the lake, as well as a number of designs for screening fish.Although numerous types of screens have been used to restrict the movement of fish either into or out of wetlands, most do not achieve the best environmental outcome in terms of allowing the free passage of native fish and other fauna while restricting the movement of Carp and other unwanted species.

Project aim and methods: Fishing/tagging activities and monitoring in the lake proper were undertaken in association with delivery of an environmental watering to Lake Bonney, and installation of a prototype wetland carp separation cage, to evaluate:

The response of Carp and native fish during the provision of environmental water, and therefore the need to accommodate the passage of large-bodied native fishes during future water allocations; and

The species diversity, abundance and size structures of captured fish (Carp and large-bodied fishes)

Two new carp exclusion screens (jail bars with 31mm apertures between the bars and square grid-mesh with 44 x 44 mm internal dimensions) (Fig 2) were trialled in the culverts to evaluate:

their effect on flow velocity; and,

whether an angle-mount and the high flow-velocities in the culvert would combine to clear the screens by pushing debris towards the water’s surface (and potentially over the top of the screen).

Findings: Scientific sampling and commercial fishing activities within the lake and inflow point, combined with fish tagging, allowed estimation of the resident population of several large-bodied fish species (native and alien), and their response to inflow. The size of the resident adult Carp population was estimated via a Peterson mark-recapture tagging experiment at 44,606 individuals. A similarly large but unquantified biomass of Bony Herring was also detected. Otherwise, only three large Freshwater Catfish and two Golden Perch were recorded, suggesting the lake’s large-bodied native fish population is very low (with the exception of Bony Herring).

Carp were observed to aggregate in large numbers around the inflow point, and spawning activity was observed within 24 hrs. Their efforts to exit the lake via the culverts was blocked by the carp screen. In contrast, relatively few large Bony Herring and no other large-bodied native fish were captured near the inflow point, however thousands of juvenile Bony Herring were observed in January 2010 when Carp were absent.

Significant refinements to strengthen Carp screens; enable them to pivot; and, prevent public access were required to enable carp screens to operate without fouling with debris, and to prevent vandalism. When set to an angle of ~33° fouling and flow constriction was significantly reduced. Most entrained fish and turtles were also able to pass over the top of this design.

Lessons learned and future directions: Although the cage operated according to its intended design and function during the 2010 trial, some operational issues were observed, necessitating refinements that have resulted in a pragmatic, adaptable and safe device.

Fixed screens such as grid mesh and the ‘jail bar’ design should not be used at wetlands like Lake Bonney that have high flows and easy public access, because:

impeding Carp movement is inefficient and often obstructs native species

regular maintenance is required

they tend to deteriorate over time, and can be easily vandalised

they can compress Carp into wetlands (ie juvenile Carp pass through a screen and grow to a point where they cannot move out though the screen).

While commercial fishing can be a valuable tool for controlling Carp, it is of limited use as a ‘stand alone’ technique as netting a proportion of adult fish does not stop Carp from spawning.

The level of by-catch (356 Bony Herring, as well as a few Golden Perch, Goldfish (Carrassius auratus) and Birds) signals the need to survey the resident native fauna on a site-by-site basis prior to installing any Carp management infrastructure. Also, the motivation of Carp to migrate out of the lake decreased over time, suggesting that harvesting should occur in the early stages of the lake being filled.

Stakeholders and Funding bodies: This project was funded through the Murray-Darling Basin Authority’s Native Fish Strategy.

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